Machine for pulverizing material



Aug. 12 1924. 1,504,781

R. E. H. PQMEROY MACHINE FOR PULVERIZING MATERIAL Filed Feb. 27, 1922 FIE. 1

OOGOGBOOOODOGOOWQOOOGQ@ Patented Aug.l 12, 1924.

UNITED STATES PATENT OFFICE.

RALPH E. E. POMERO'Y, lOIE CANTON, OHIO.

vF013 PULVERIZING MATERIAL.

Application led February 27, 1922. Seria1 No. 599,417.`

certain improvements in the removal frommills containingy a charge consisting of hard bodies such as metal balls, pipes, rods, cobble stones, etc., and material being broken up and pulverized by impact with and abrasion by the hard bodies, of material which has been reduced to the desired degree of fineness. Prior-to the invention described and claimed in an application filed by me June 1st, 1920, Serial No. 474,07 9 the removal of the fine material was effected in most cases by a current of air entering through one of the trunnions and escaping through the other trunnion. In such method only such particles as are thrown out of the charge by the movements of'its elements are caught and removed by the air current, and only those particles on or near the inner surface of the charge will be thrown out. In the apparatus described and claimed in the above application, wherein air enters the periphery of the drum, fine particles will be forced from the interior of the charge towards the inner surface. As the particles in moving from the interior of the charge will have to pass around the larger bodies comprising the charge, the rate of segrega-Q tion of the fine particles will not approxi-t mate the rate of reduction of the material to the desired degree of iineness.

The invention described herein has for its object the withdrawal of particles which have been; reduced to the desired degree of fineness from the charge as soon as possible after they have attained such condition.` llt is a further object of the invention to yprovide for 'an increased efliciency in reduction by abrasion and impact. The invention is hereinafter more fully described and claimed.

In the accompan ing drawings forming a part of this speci cation, Fig. 1 is a sectional elevation of a reducing mill embodying the' improvement claimed herein and" Fig. 2 is a transverse section of the same.

n the practice of the invention it is preferred to employ a construction of mill substantially as shown and described in the application above referred to, consisting of a shell 5 provided 4,with headsy Shaving trunnions 7, 7, mounted in suitable bearings 8. The shell may be rotate by any suitable means as for example by a driven pinion 9 engaging a gear wheel 10 secured to one of the heads 6. The shell is enclosed by a casing 12 closely fitting against the periphery of the shell but not suiiiciently tight to.

prevent the 'free -rotation of the shell. The shell is provided interiorly with'a lining consisting of longitudinal blocks 15 extending substantially the full length of the shell and so constructed as to form passages communicating at their outer ends with perforations in the shell and adapted to direct currents of air flowing therethrough in'directions at an acute angle to radii of the shell.` As clearly shown in Fig. 2 the casing is provided with anenlargement forming an air chamber 4 extending substantially the entire length of the shell and having such a width that a plurality of rows of perforations in the shell will be in communication with the chamber at the same time.

The trunnions are made hollow and one of them is connected to'a source of supply of the material to be reduced,`as 7. The other trunnion is provided with an extension 17 projecting into the shell. This extension or member which ispreferably made with an external diameter approximately equal.` to the internal diameter of thetrunnion to facilitate the renewal of a member, has one end supported by the trunnion 7a, while the opposite end may be supported in any suitable manner as for example by means of a shaft 18 projecting from the end of the member 17 through the trunnion 7 and supported by a bearing 19. In' order to facilitate the removal of material as soon as possible after it has been reduced to the desired gree of iineness, it is preferred to make t e member 17 tubular and to .perforate its wall as shown, the perforations bein made of a size dependent on the desiredv neness of the material.

Ian operating the mill, such quantity of balls or'other round bodies are charged into the shell and the latter rotated at such a lspeed that although there will bea loosening approximately proportionately to the movement above such plane, will be a sagginginwardly of such portion until the innermost balls rest against the member 17. The action or movements of different portions of the charge is shown in Fig. 2. During the movement of the charge between planes coincident with line a-b and 0;-0, the ele. ments of the charge are pressed outwardly.

by the combined action of centrifugalforce and gravity. Above the line rf-c gravity will act at an angle to the direction of centrifugal force but not suiliciently to cause movement of the balls. Above the line a-d the gravital pull on the balls tends to pull the balls inwardly and when the charge passes the line athe gravital pull will overcome the centrifugal action to such an extent that the charge will sag inward ency to arch and prevent any balls rolling.

down along the surface of the charge below the line` 1l-d, butas the member 17 rotates with the shell balls resting on the member will be carried along to the left prevent-infr any complete arching, and balls will 'roll down along the Surface of the charge below the line a-d. The balls which have been carried to the left will drop down off the member 17 to the bottom of the shell.

It will be observed that in the described operation of the mill` there are two fields or areas where vabrasion will occur, to-wit: along the surface of the portion of the charge temporarily supported by the member 17 and along the surfaces of the portion of the charge below the line a-c.

In the usual operation of mills of this type some of the balls mayhave a slight drop but for the most part they will roll down along the inner surface of. the charge. In the method described herein the inwardly turning or sagging movement of the upper portion of the charge is arrested and the direction of movement of a large per cent of the balls is deflected to the left ofthe member 17, and as the balls so deflected will drop a distance approximately equal to half the diameter of the shell they will impart a com paratively heavy blow to the charge on the bottom of the shell.

In other words there is Ian inward turning movement of the section of the charge above the line a-o, the outer portion of the section or those closely adjacent to the shell being carried up, while the inner portions move down, such downward or turning movement increasing proportionately to the distance above the initial' point. `The distance of the initial point of this turning movement is dependent on the rate of rotation of the shell and the faster such rate the higher will that point be above the line (z 0.

In the operation of the apparatus the shell is given such a speed that the turning section of the charge will encounter the member 17 and further turning will be arrested. Or the speed of rotation of the shell should be such that the balls in contact with the shell will drop when they have been carried to a vertical plane assing to the right of the axis of the sheli as shown in Fig. 2.

In addition to the reducing efiiciency incident to the operation of the a paratus herein described, a corresponding y great eiliciency in the withdrawal of the reduced material is obtainedy by constructing the member 17 in the form of a tube having perforated walls and effecting the removal `of the reduced material through the tubular member, which in order to mamtain velocity constant is preferably made tapering as shown.

As is well known, the pieces of material being reducedy are thoroughly intermingled with the balls on other hard bodies, and such pieces have the same cycle of movement as the balls, and hence the pieces will move with the balls in the portion of the charge above and to the left of the line .a-e towards the member 17, will roll down with the balls along the surface of the portion of the charge supported by the member and pass to the left -of the member and will also roll'down the exposed surface of the portion of the charge below the line af-c. In effect, the tubular member is embedded in the charge which is caused to move around it and during such circulation the elements of the charge are changing their relative positions. `As' hereinbefore stated the currents of air employed for removing the finished product enter through perforations in the perimeter of the shell, pass through the charge into the shell and escape laden with pulverized material through the perforations in the member 17 and flow along'the same to the pipe connected to its outer end to a point of use or storage.

As is well known in the art, centrifugal force acts most effectively on the balls lying against the shell and is less effective on balls nearer the center, and hence as the gravital force is constant there will be after the balls have passed above the line a-c a sagging down of the balls nearer the center before any such tendency would be felt by balls in the same horizontal plane but near the periphery.

As the charge moves up the balls near the center will respond more and more to such sagging tendency, and balls further from the center will respond but in a lesser degree to such sagging tendency until a point is reached Where the balls in' contact with the shell will drop away. The location of the point is of course dependent on the speed at which the shell/is rotated.

I claim herein as my invention:

1.. An apparatus for pulverizing frangible material having in combination a rotatable Shell having perforations in its periphery, a perforated outlet pipe arranged Within the shell and having its outlet end outside of the shell, and means for causing currents of air to enter through the peripheral openings in the shell, and to flow out through the perforated pipe.

2.l An apparatus' for pulverizing frangible material having in combination a rotatable shell having perforations in its periphery, a

- perforated pipe arranged axially Within the shell and having end projecting outside of the shell and means for causing air to enter the shell through the perforations in the shell and to How through the perforations in the shell and to flow through the perforated pipe.

3. An apparatus for pulverizing frangible material having in combination a rotatable shell provided with hollow trunnions and having perforations in its perimeter, bearings for said trunnions, means for feeding material through one of the trunnions, a perforated portion extending through the other trunnion into the shell and means for causing air to enter the shell throughthe peripheral perforations and to flow out through the perforated pipe.

4C. An apparatus for pulverizing frangible material having in combination a rotatable Ashell having perforations in its periphery,

a pipe arranged axially in the shell and having one end projecting beyond the end of the shell and having the portion Within the shell perforated, and means for causing currents of air to flow in substantially radial directions within the shell.

ln testimony whereof, l have hereunto set my hand.

RALPH E. H. PoMnaoY.- 

